Clinical UM Guideline

Subject:

Lumbar Discography

Guideline #:

CG-SURG-29

Current Effective Date:

04/15/2014

Status:

Reviewed

Last Review Date:

02/13/2014

Description

Lumbar discography involves the injection of one to three (1-3) ml of contrast agent usually followed by CT imaging to evaluate the nature and extent of vertebral disc abnormality. The objective is also to characterize the pain response (if any) on disc injection and observe whether this reproduces the individual's usual pain so as to confirm the disc as the source of the back pain.

Noninvasive diagnostic studies have failed to provide sufficient diagnostic information regarding the origin of pain; AND

There is no evidence of contraindications such as severe spinal stenosis resulting in intraspinal obstruction, infection, or predominantly psychogenic pain.

Inaddition to those listed above, at least ONE of the following indications must be present:

A high index of suspicion for discogenic pain and the pain is severe enough to consider surgical intervention, OR

For failed back surgery individuals, to distinguish between painful pseudoarthrosis or a symptomatic disc in a posteriorly fused segment.

Not Medically Necessary:

Lumbar discography is considered not medically necessary for individuals who do not meet the medically necessary criteria set forth above.

Coding

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

CPT

62290

Injection procedure for discography, each level; lumbar

72295

Discography, lumbar; radiological supervision and interpretation

ICD-9 Diagnosis

[For dates of service prior to 10/01/2014]

All diagnoses

ICD-10 Diagnosis

[For dates of service on or after 10/01/2014]

All diagnoses

Discussion/General Information

Low back pain occurs in approximately 70-85% of all people at some time during life. Pathology of one or more lumbar discs is felt to be the cause of low back pain in many cases. Lumbar discogenic pain due to internal disc disruption (IDD) remains a topic of wide controversy, is poorly understood, and has been estimated to account for as many as 39% of individuals with low back pain. While imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI) and myelography may identify disc pathology, they may be unable to determine if a diseased (disrupted) disc is the source of low back pain. Zhou (2006) reported that MRI lumbar imaging has a low sensitivity (26.7%-59%) and high false-positive (24%) and false-negative (38%) rates when used in screening for the existence of IDD.

Lumbar discography is an invasive diagnostic procedure proposed for the evaluation of chronic low back pain when disc pathology is suspected and surgery is being considered. Lumbar discography is used to determine if a disc is painful on injection and if the pain elicited reproduces the individual's low back pain. The current method for this procedure involves the pressure-controlled injection of radiopaque dye into the intervertebral disc followed by CT imaging. CT imaging is used to evaluate the integrity of the central disc and annular ring to identify tears or disruption as a source of low back pain. In addition to using lumbar discography to identify disc morphology (pathology), proponents also use the test as a measure of "disc nociception" and argue that injecting a disc that is compromised and a pain generator will cause pain that reproduces the individual's pain syndrome. Only a few studies have looked at the incidence of false positive discography induced pain in asymptomatic volunteers and have reported it to be as low as 0% (Derby, 2005), but also considerably higher, 25%, (Carragee, 2006). Since discography is invasive, it is performed only after other diagnostic tests have failed to isolate the cause of back pain or are equivocal or inconsistent. Discography is usually reserved for individuals who have had back pain for an extended period of time and who have not obtained satisfactory pain relief from noninvasive treatments such as modified activities, medication, and physical therapy.

The validity of lumbar discography as a diagnostic tool has been studied extensively, but controversy has been ongoing for over 50 years. While discographic imaging alone may not be useful, i.e. the presence of a degenerative disc will not predict whether a disc is painful in a particular individual (Slipman, 2001), the contemporary use of lumbar discography combines CT discography imaging with pain provocation to assist in the selection of individuals for intradiscal therapies. Shah and colleagues (2005) and Buenaventura and colleagues (2007) performed extensive reviews of the literature evaluating the diagnostic accuracy of discography in the management of chronic spinal pain. Studies were scored according to the Agency for Healthcare Research and Quality (West, 2002) and QUADAS (Whiting, 2003) rating scales for diagnostic testing. For inclusion, studies first had to meet at least 50% of the total possible points for each scale. Evidence was then classified into five levels: conclusive, strong, moderate, limited, or indeterminate. The authors concluded in their review of the evidence through November 2006 that there is strong evidence for the diagnostic accuracy of discography as an imaging tool and for its ability to evoke pain. They also concluded there is strong evidence to support the role of discography in identifying a subset of individuals with lumbar discogenic pain. "Strong" evidence in this review was defined as "Research-based evidence from at least 1 properly designed randomized controlled trial; or research based evidence from multiple properly designed studies of small size; or multiple low quality trials." These conclusions are similar to those of Manchikanti and colleagues who undertook a detailed review of the literature (Manchikanti, 2008). These authors concluded that lumbar discography was strongly recommended based on observational studies.

A contrary opinion is presented by Wichman (2007). His review of the literature suggests that pain provoked by discography of discs appearing normal on MRI was likely due to internal disc disruption, increased pain sensitivity, psychological state, central hyperalgia, and technical difficulty of the procedure. This author contends that these causes of positive pain provocation would not be amenable to invasive treatment. In his opinion, an invasive diagnostic procedure to identify problems best treated with conservative management was not appropriate.

Carragee (2000), from a group of 240 subjects who had undergone single-level discectomy for sciatica, recruited 20 asymptomatic volunteers for three-level lumbar discography. A second group of 27 symptomatic individuals, after single-level discectomy, with intractable low back pain also underwent discography. Raters who were blinded to the control versus experimental status of the subjects scored the MRI images, discogram, and discography videotapes of the subjects' pain responses. The study, although small, showed that 40% of asymptomatic individuals with normal psychometric testing who previously had undergone lumbar discectomy had significant pain (2.1 of 5) on injection of discs that had previous surgery. The results in the symptomatic post-discectomy group were very similar. In this group, 43% of participants who scored normal on psychometric testing had the same level of pain provocation on discography (2.1 of 5). This study also found that symptomatic individuals with abnormal psychological profiles have significantly higher rates (70%) of positive disc injection than either asymptomatic volunteers or symptomatic subjects with normal psychological screening.

However, in a randomized prospective study of a group of 50 individuals with low back pain, 25 with and 25 without somatization disorder, Manchikanti (2001) concluded that provocative discography provides similar results in individuals with or without somatization. Results showed positive provocative discography in 46% of participants in the somatization group compared to 54% in the non-somatization group.

The ability of discography to identify lumbar disc disease has improved with advances in imaging techniques, the use of CT rather than plain X-ray, and the use of standardized pain assessment tools. Limitations to the study of discography include an incomplete understanding of the mechanisms generating discogenic pain, reliance on subjective information from the individual, the potential for psychological/compensation issues to influence reported pain/outcome, and the observation that normal tissue in areas adjacent to chronic pain generators may be more sensitive to painful stimuli.

There are few studies comparing surgical outcomes between individuals who have had discography pre-operatively and those who have not. The limited evidence which is available is conflicting, and while discography combined with CT may be more accurate than other imaging tests in detecting degenerative disc disease, its ability to result in improved surgical outcome is unproven (Cohen, 2005). Madan and colleagues (2002) reported on their findings of a non-randomized study of 73 consecutive participants who underwent postero-lateral interbody and posterior spinal fusion for discogenic low back pain refractory to medical therapies. The first 41 participants were selected without the use of discography, while the remaining 32 participants were selected for surgery only if their pain syndrome was provoked with lumbar discography. The two groups were felt otherwise to be similar with regards to age, gender, psychometric profile and nature of disc disease seen on pre-operative imaging. Average follow up was 2.8 years for the first group and 2.4 years for the second group. Using a standardized disability scale, Oswestry, there was no significant difference in surgical outcome between the two groups.

To date, a significant limitation of studies to establish the diagnostic accuracy of provocative lumbar discography has been the absence of an agreed upon gold standard. Some studies have used discography as a pre-surgical screening tool and concluded the validity of discography depends on the outcome of a lumbar spinal fusion, a controversial surgical treatment. Others argue that abnormal disc morphology should serve as a gold standard to judge the accuracy of lumbar discography rather than the response to an as yet unproven treatment for a disease difficult to treat. Sample sizes for most studies have been small as ethical concerns have prevented invasive tests on large individual samples that may not have disease. For this reason, although the majority of studies have been prospective, most have not been randomized, controlled or blinded. In the review of 69 studies meeting a minimal evidence threshold selected by Buenaventura (2007) outlined above, while 39 studies were prospective, only 8 studies were controlled, just two were randomized (Manchikanti, 2001) and only one small observational study (Carragee, 2000) used a prospective, controlled, and blinded design. No randomized, controlled, and blinded studies of discography have been reported.

Divided opinion on the utility and application of lumbar discography can be seen in the position statements of professional societies. The American Association of Neurological Surgeons (Resnick, 2005) position statement does not recommend discography in subjects with normal lumbar MRI, but does acknowledge its role in the evaluation of individuals with low back pain with: (1) abnormal interspaces identified on MRI; (2) the investigation of adjacent-level disc disease; and (3) as a means to rule out non-organic pain from surgical consideration.

The North American Spine Society's broader recommendation (Guyer, 2003) limits the use of lumbar discography to select clinical indications including (1) correlation of an abnormal disc with clinical symptoms including pain following a previously operated disc or lateral disc herniation, (2) evaluation of persistent, severe symptoms when other diagnostic tests have failed to reveal a disc as the source of pain, (3) evaluation of a failed surgical intervention to diagnose symptomatic pseudoarthrosis, recurrent disc herniation, (4) evaluation prior to spinal fusion to determine if discs within the proposed fusion are symptomatic and adjacent discs are normal, and (5) evaluation of individuals being considered for minimally invasive surgical intervention.

The American Society of Interventional Pain Physicians (ASIPP) guidelines for interventional techniques in the diagnosis and treatment of chronic spinal pain point out that under ideal circumstances, the gold standard or criterion for the diagnostic accuracy of discography would be obtained by tissue confirmation of the presence or absence of disease; however, surgical inspection of a degenerated disc cannot determine if discogenic pain is or is not present. Therefore, the greatest challenge concerning discography is the "gold standard: dilemma and the interventions used as a result of the test. The ASIPP concluded that the diagnostic accuracy of lumbar discography when compared to other non-invasive modalities of assessment was fair and that there is limited evidence the evidence supporting the use of discography prior to surgical procedures (Manchikanti, 2013).

MPTAC review. Updated review date, Rationale, Reference and History sections. In the first bullet of the medically necessary clinical indications, changed the word "consisted" to "persisted." No change to intent of patient selection criteria. Removed the Place of Service/Duration section from the document.